Facsimile apparatus using a memory management device having empty memory block maintenance function

ABSTRACT

A memory management device enables to effectively use a memory which permits its stored data to be erased only in blocks. A facsimile apparatus is arranged to temporarily store sending information and received information in the memory and then to send or receive the information. The facsimile apparatus includes a flash memory whose data is allowed to be erased only in blocks and a storage unit for storing the sending or the received information in its own blocks if the sending or the received information is stored in the flash memory.

This is a division of application Ser. No. 08/335,343 filed Nov. 3,1994, now U.S. Pat. No. 5,598,548.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a memory management device whichoperates to divide a memory into storage blocks so that the storedcontent is allowed to be erased only in blocks and a facsimile apparatuswhich is arranged to use the memory management device.

2. Description of the Related Art

Dynamic RAMs (DRAM) and static RAMs (SRAM) are representatively used asmemories. The DRAM needs to periodically rewrite data even if it ispowered on, while the SRAM operates to hold data only if it is poweredon. Both of these memories fail to hold their data without their powers.These memories are required to have a spare battery for backing them upwhen the power is interrupted. On the other hand, the ROMs are capableof holding data if the power is off, while the ROM often has difficultyin rewriting data. The EPROMs are capable of rewriting data again andagain only if ultraviolet rays are applied thereto. Regrettably,however, the EPROM is required to rewrite all the content storedtherein. The EEPROM allows a program stored therein to be electricallyerased. The program can be erased also in bits. Further, a kind of ROMcalled as a flash memory has been currently used. The flash memory has acapability of erasing the stored data in blocks, that is, block byblock.

As mentioned above, nowadays, many kinds of memories have beencommercially made available. Those memories have their merits anddemerits. It is now desirous to provide such a memory as keeping thesame ease of use as the DRAM or the SRAM and needing no power back-up.The DRAM or the SRAM is capable of easily changing a value of 1 or 0 atthe current bit into a value of 0 or 1. On the other hand, the ROM keepsa value of 1 at any bit when it is in the initial state. If some data iswritten in the ROM, the values of 1 at the bits corresponding to thewritten data are changed to the values of 0. To return the 0's to the1's, the ROM is required to do an erasing operation. Hence, unlike theDRAM, the ROM cannot easily change from the 0's to the 1's. For erasingthe stored data, the EPROM enables to only erase all the data. The flashmemory enables to erase the data only in blocks. Further, like the DRAM,the EEPROM has a capability of erasing the data in bits, that is, bit bybit. The EEPROM, however, is so expensive that it is not made availablefor general-purpose goods.

SUMMARY OF THE INVENTION

The present invention is designed to overcome the above-mentionedshortcomings, and it is an object of the present invention to provide amemory management device which achieves more efficient use of a memorywhose data is erased only in each storage block and a facsimileapparatus which is arranged to use the memory management device.

In carrying out the object, according to a first aspect of the presentinvention, a memory management device provides a memory which enables tomerely reverse the initial value at each bit and control means whichoperates to control the memory as considering the bit-by-bit reversedstate from the initial state on the memory as a starting state.

According to a second aspect of the present invention, a memorymanagement device provides a memory which operates to divide its storagearea into blocks and erase the data only in a block-by-block manner,control means which sectionalizes the blocks according to the erasingcondition of the information to be stored and store the information inthe block having the corresponding erasing condition, and erasing meansfor erasing the stored content of the block only if the erasingconditions of all the stored informations about each block are met.

According to a third aspect of the present invention, a facsimileapparatus for temporarily storing the sending information or thereceived information in a memory and performing a series of operationscontaining sending or recording, provides the memory which operates todivide a storage area into blocks and erase the data only in blocks andstoring means which operates to store the received information or thesending information in the sectionalized blocks if the information is tobe stored in this memory.

According to a fourth aspect of the present invention, a facsimileapparatus for temporarily storing sending information and receivedinformation in a memory and then performing a series of operationscontaining sending or recording, provides the memory which operates todivide a storage area into blocks and erase the data only in blocks andcontrol means which operates to read the data from the head of a groupof empty blocks concatenated in a predetermined sequence if data is tobe stored in one of the blocks of the memory.

According to a fifth aspect of the present invention, a facsimileapparatus for temporarily storing sending information or receivedinformation in a memory and then performing a series of operationscontaining sending or recording, provides the memory which operates todivide a storage area into blocks and erase the data only in blocks,storing means which operates to sectionalize the blocks for the sendinginformation and the received information, and erasing means whichoperates to erase the sending information of one block when all thesending informations of the block are sent out or erase the receivedinformation of another block when a series of operations containingrecording are done for all the received informations of the block.

According to a sixth aspect of the present invention, a facsimileapparatus for temporarily storing sending information or receivedinformation in a memory and then performing a series of operationscontaining sending or recording, provides the memory which operates todivide its storage area into blocks and erase the data only in blocks,erasing means which operates to erase the stored content of the memoryin blocks, and control means which operates to couple the block whosecontent is erased by the erasing means to the tail of a group of emptyblocks concatenated in a predetermined sequence.

According to a seventh aspect of the present invention, a facsimileapparatus for temporarily storing sending information or receivedinformation in a memory and then performing a series of operationscontaining sending or recording, provides the memory which operates todivide its storage area into blocks and erase the data only in blocks,erasing means which operates to erase the content stored in the memoryin a block-by-block manner, and control means which operates to countthe empty blocks if a sending or receiving operation is requested whilethe content of the block is being erased, perform the requestedoperation if it is equal to or more than the regulated number or keep toerase the data stored in the blocks until the number of actual emptyblocks reach the regulated number, and then perform the requestedoperation.

According to an eighth aspect of the present invention, a facsimileapparatus for temporarily storing sending information or receivedinformation in a memory and then performing a series of operationscontaining sending or recording, provides the memory which operates todivide its storage area into blocks and erase the data only in blocks,erasure indicating means for indicating erasure of a block content,display means which operates to change the management data of anindicated block to the content of the block according to the erasingindication and display the erasing information of the block, and erasingmeans which operates to erase the content of the block whose managementdata is changed after the erasing information is displayed in thedisplay means.

In the first aspect of the present invention, in the case of handlingthe memory, the memory is just allowed to be reversed from the initialstate. Hence, the state reversed from the initial state in a bit-by-bitmanner is used as a flag representing the starting state of the memory.This means that the initial state represents the waiting state.

In the second aspect of the present invention, the used memory operatesto divide the storage area into blocks and erase the data only inblocks. Each block stores only the pieces of information having the sameerasing condition. If the erasing conditions of all the pieces ofinformation in the block are met, the informations in the block areerased. The informations having the same erasing condition often have ashort period from when it is stored to when the erasing condition ismet. On the other hand, if the pieces of information stored in one blockhave a different erasing condition rather than any other condition, arelatively long period is required until the erasing conditions of allthe pieces of information stored in the block are met. By storing theinformations having the same erasing condition in the same block,therefore, the content of the block is allowed to be quickly erased. Theblock is used for storing the new information. This serves to enhancethe using effect.

In the third aspect of the present invention, in a case that the memoryarranged to divide the storage area into blocks and erase the data inblocks is provided to the facsimile apparatus as a memory for storingthe sending and receivied informations, if, at first, the sending or thereceiving information is stored in one block, only the same type ofinformation stored at first is stored in the block, so that both thereceived and the sending informations are not allowed to be stored inone block. If one kind of information is stored in one block and theother kind of information is stored in another block, the period takenwhen all the sending data in one block is sent or the period taken whenall the receiving data in the block is recorded is shorter than theperiod if both kinds of data are stored in one block.

In the fourth aspect of the present invention, in a case that the memoryarranged to divide the storage area into blocks and erase the data onlyin blocks is provided to the facsimile apparatus as a memory for storingthe sending and the receiving informations, the empty blocks areconcatenated in sequence for management so that the blocks are pickedfrom the head one for storing the data therein. This makes it possibleto evenly use all the blocks, thereby reducing the probability offailure in each block and hence prolonging the life of the memory.

In the fifth aspect of the present invention, in a case that the memoryarranged to divide the storage area into blocks and erase the data onlyin blocks is provided to the facsimile apparatus as a memory for storingthe sending and the received informations, either one of the sendinginformation and the receiving information is stored in one block. If allthe recorded sending informations are sent from the block where they arerecorded, the data in the block is erased. On the other hand, when allthe receiving informations are recorded in the block for recording onlythe received information, the overall information in the block iserased. In this state, the probability of establishing the erasingcondition about all the informations in each block is higher than theprobability given when both of the sending and the received informationsare stored in one block. Hence, the period from when the data is storedin one block to when the data is erased from the block is reduced,thereby allowing the using ratio of the blocks to be enhanced.

In the sixth aspect of the present invention, in a case that the memoryarranged to divide the storage area into blocks and erase the data onlyin blocks is provided to the facsimile apparatus as a memory for storingthe sending and the received informations, if the erasing condition ismet and the data is erased in blocks, the block whose content is erasedis coupled to the tail of the empty blocks concatenated in thepredetermined sequence. The blocks whose contents are erased are coupledin the erasing sequence. Hence, if the empty blocks are used, thoseblocks are allowed to be evenly used.

In the seventh aspect of the present invention, in a case that thememory arranged to divide the storage area into blocks and erase thedata only in blocks is provided to the facsimile apparatus as a memoryfor storing sending and received informations, the erasing meansoperates to erase the block data if the erasing condition is met in theblock. If the sending or receiving operation is requested while theblock data is being erased, it is checked whether or not the number ofempty blocks is equal to or more than the given number before theoperation is executed. This makes it possible to secure storage of theregulated sending or receiving amount. If the number is less than theregulated number, the operation is executed to erase the data of theblocks whose erasing conditions are met until the number of the emptyblocks reaches the regulated number. Then, the sending or receivingoperation is executed.

Moreover, in the seventh aspect of the present invention, in a case thatthe memory arranged to divide the storage area into blocks and erase thedata only in blocks is provided to the facsimile apparatus as a memoryfor storing the sending and the received informations, the receivedinformation may contain the information like a received message of ananswering phone which is not permitted to be erased without judgement ofa receiver. In this case, the erasure indicating means operates toindicate the erasure. In response to this indication, the display meansoperates to display the erasure of the block as keeping only the erasingmanagement information of the block in the state that the block iserased. The erasing means operates to erase the content of the block. Bythis operation, an operator for indicating the erasure can quickly makesure that the erasure is done through the effect of the erasureindicating means. Hence, the operator does not need to wait until theactual erasure is done.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing an overall arrangement of a memorymanagement device according to an embodiment of the present invention;

FIG. 2 is a view showing an arrangement of a flash memory used in theembodiment;

FIG. 3 is a view showing an arrangement of an erase block managementarea;

FIG. 4 is an explanatory view illustrating the use of an erase block ineach file;

FIG. 5 is a table showing an arrangement of a memory block managementarea;

FIG. 6 is a flowchart showing a checking operation of the flash memorywhen it is powered;

FIG. 7 is a flowchart showing an operation of writing data to the flashmemory;

FIG. 8 is a flowchart showing an operation of erasing data from theflash memory; and

FIG. 9 is a view showing an example of displaying the erasing state ofthe flash memory.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Later, the description will be oriented to a memory management deviceaccording to an embodiment of the present invention with reference tothe drawings.

FIG. 1 is a block diagram showing an arrangement of the memorymanagement device. In FIG. 1, a numeral 1 denotes a network control unitwhich is connected to a line 2 so that the network control unit 1controls the connection with a line exchange network, concretely,performs calling, releasing or dialing. A numeral 3 denotes a modemwhich operates to modulate data to be sent into a signal or demodulatethe received data into an original signal. The signal is suitable fordata transmission through a phone line. A numeral 4 denotes a readerunit which operates to read a manuscript to be sent or copied. A numeral5 denotes an operation unit through which an indication given by anoperator such as a phone number or settings of an answering phone. Anumeral 6 denotes a display unit which operates to display a response ora guide to the operator such as an inputted phone number. A numeral 7denotes a recording unit which operates to print the received data orthe data read by the reader unit 4.

A numeral 8 denotes an image processing unit which operates to magnify,reduce, rotate or move the read image or the image to be recorded. Anumeral 9 denotes a speech recording and reproduction control unit whichoperates to control recording of a speech in the answering phone orreproduction of the speech through a speaker. A numeral 11 denotes aflash memory which operates to store the received information, the datato be sent from the memory, or a speech message of the answering phone.A numeral 12 denotes a memory control unit 12 which operates to controlthe flash memory 11 for storing data to be sent by a facsimile, datareceived by the facsimile or speech data sent by a phone. A numeral 13denotes a display control unit which operates to control the reader unit4, the operation unit 5, the display unit 6 and the recording unit 7. Anumeral 14 denotes a main control unit which operates to control theoverall arrangement of the device and decode the data received by thefacsimile or code the data to be sent thereby.

FIG. 2 is a view showing an arrangement of the flash memory 11 used inthe facsimile apparatus of this embodiment. As shown in FIG. 2, theflash memory used in this embodiment has a volume of 1 MB. The storagevolume is divided into erase blocks, each of which has a volume of 64KB. The stored data is erased in units of one erase block. Each eraseblock is composed of one management area for storing managementinformation and 63 memory blocks each for storing data. This managementarea is composed of an erase block management area for storinginformation indicating the state of the corresponding erase block and amemory block management area for storing information indicating thestate of the corresponding memory block. As the memory block managementarea, 63 areas are prepared in order to correspond to the 63 memoryblocks respectively.

FIG. 3 is a view showing the arrangement of the erase block managementarea shown in FIG. 2. Now, each item provided in the erase blockmanagement area will be described later. The management area holds twotypes of informations, that is, management information and storedinformation. The management information contains a block erasing state,a block using information, an in-block memory information, a file item,an erase block location, and a next erase block number. The blockerasing state indicates whether or not the corresponding erase block islogically erased. The block using information indicates whether or notthe erase block is in use. The in-block memory information indicateswhether or not a memory block in the erase block is empty, that is, anynon-used memory block is left. The file item indicates what kind ofinformation is stored in the erase block. The informations indicated asthe file item contain data to be sent (referred to as sending data),received data, a received message and a response message of an answeringphone, transmission to be done by a timer (referred to as timertransmission), and a bulletin board to be sent by a facsimile (referredto as facsimile bulletin board). Each erase block stores only one kindof those informations. Another kind of information is stored in anothererase block. This is because the data is erased in units of one eraseblock. If each erase block stores the same kind of information, all theerasing conditions of the stored informations are met for quite a shorttime. The erasing condition means the termination of transmission of thedata for the transmission data or the termination of recording the datafor the received data. On the condition, the data is allowed to beerased from the flash memory.

The location of the erase block actually indicates the location wherethe empty erase blocks are ranged in a column for waiting for the datainput. With reference to FIG. 4, the using state of the erase block willbe described. A file is prepared for each kind of informations to bestored. Each erase block is made to be a leased block for the file whenthe erase block is used for each file. Each erase block is generated asa leased block for each file. When the total volume of the erase blockgoes beyond 64 KB, the next new erase block is generated and then ischain-coupled to the full erase block. The empty blocks arechain-coupled so that it is used from the head of the block chain.Further, the data-erased block is given back to the tail of the emptyblock chain. This makes the erasing time of each erase block uniform.Going back to FIG. 3, the next erase block number indicates the numberof a next chained erase block if the erase block is chain-coupled to theempty blocks.

The storage information of FIG. 3 is a flag for representing the stateof the management information title located in the left side. Except thefile item contained in the management information, the initial state isindicated by 1 and the starting state is indicated by 0. For example, inthe block erasing state, a non-used state (initial state) is 1, while aused state is 0. For the file item, each kind of information has thecorresponding number. The next erase block number indicates FF(hexadecimal representation) given when the erase block is coupled tothe tail of the empty blocks. If the next erase block is coupledsimilarly, the next erase block number indicates the number (00 to FE)of that erase block. As mentioned above, the initial state is 1 and thestarting state is 0. This is because the flash memory allows theinversion of 0 to 1 to be executed only by erasure, so that theoperation of writing data to the memory allows only the change of 1 to0.

FIG. 5 shows an arrangement of each memory block management area in theerase block management area shown in FIG. 2. Like FIG. 3, the memoryblock management area holds the management information and the storageinformation. The management information contains a file erasing state, afile using information, a next erase block location, a next memory blocklocation, a memory in-block data length, a directory state, a directoryinformation, a next page erase block location, and a next page memoryblock location. The file erasing state indicates whether or not a filestored in the corresponding memory block is erased. This information ismeaningless unless it is related to the next file using information andany file is stored. The file using information indicates whether or notthe corresponding memory block is in use. As shown in FIG. 4, since theerase blocks being used are coupled for each file, the next erase blocklocation indicates the number of an erase block coupled next to theerase block to which the memory block belongs. If the subject eraseblock is located at the end of the chain, the number indicates FF. Thenext memory block location means the number of the next located memoryblock. The memory in-block data length represents the amount of data inthe memory block by the number of bytes. In the directory state, it isdeclared that the use of the management area is prioritized if the stateis determined as "0: in use". Further, the memory blocks for each pageare collectively managed. The directory information indicates whether ornot the information is stored in the memory block(s) composing thedirectory. If so the directory information indicates "0" for "closed",while if not, the directory information indicates "1" for "not closed".The next page erase block location represents the location of the firsterase block of the next page if the data is sent or received in a pageunit. The next page memory block location represents the location of thefirst memory block of the next page. Like the description about FIG. 3,in the storage information located in the right side of FIG. 5, theinitial state is represented by 1, while the starting state isrepresented by 0.

The description will be oriented to the operation of the facsimileapparatus having the flash memory 11 arranged as described above withreference to the flowcharts.

FIG. 6 is a flowchart showing the operation of the facsimile apparatuswhen it is powered on. When the facsimile apparatus is turned on, theoperation is executed to determine whether or not data is stored (ST1).If it is determined that no data is stored, it is determined whether ornot the flash memory is formatted in a predetermined manner (ST2). Ifthe flash memory is not formatted, it is determined that the flashmemory is new. Then, the flash memory is divided into erase blocks,which corresponds to an erase unit (ST3). The generated erase blocks areall empty. Hence, these empty erase blocks are chain-coupled as an emptyblock group as described with respect to FIG. 4 (ST4).

If at the step ST1 it is determined that data is stored, it isdetermined whether or not any conflicting piece of data exists (ST5).Herein, the operation is executed to search the data whose directorystate indicates "not in use" and directory information indicates "notclosed". Such a conflicting piece of data may take place when the powerinterruption causes the operation to be suspended while a file is beingcreated. If the conflicting piece of data is found, the recovery processis executed (ST6). The recovery process varies according to the placewhere the operation is suspended. If the conflicting data may be saved,the directory of the data is changed from "not closed" to "closed". Ifit may not be saved, the data of the erase block to which the memoryblock belongs is erased. According to this operation, all the data isretrieved (ST7) and the conflicting piece of data is recovered. Then,the flow given when the facsimile is powered is terminated.

Next, the operating flow of writing data to the flash memory 11 will bedescribed with reference to FIG. 7. Any one of processes is executedsuch as sending of data from the memory, receipt of data in the memory,receipt of a speech by an answering phone, sending of data by a timer,notice of the bulletin board sent by a facsimile (e.g., as in afacsimile-on-demand system) (ST101). Then, the operation is executed tocheck whether or not the erase block is provided for the filecorresponding to the executed process (ST102). As described with respectto FIG. 4, this is executed for determining whether or not an eraseblock group is provided for each file. This is determined from the fileitem of the erase block management area shown in FIG. 3. If no eraseblock corresponding to the process is found, one erase block is obtainedfrom the head of the empty block group shown in FIG. 4 (ST104).

The file item of the given process is described in the management areaof the obtained erase block. Then, the block using information is madeto be in use and the directory state of the memory block management areais also made to be in use (securing the directory area) (ST105). Thedata of the corresponding file is written in memory blocks to which theerase block belongs (ST106). In the management area of the memory blockin which data is written, the file using information is determined to bein use and the storage information such as a number of bytes of thewritten data is written in the management area (ST107). If the data isoverflown out of one memory block, that is, there remains data left tobe written (ST108), the operation is executed to check whether or notthe in-block memory information of the management area of the eraseblock indicates "there exists empty space" (ST110). If yes (ST111), thedata is written to the next memory block (ST106) and the storageinformation described at step ST107 is written in the management area ofthis memory block. At this time, the number of the memory block in whichdata writing has just terminated is written in the location of the nextmemory block to this memory block management area, and the memory blocksare chain-coupled with each other. By iterating the loop composed of thesteps ST106 to 108, 110 and 111, the data is written in the memoryblock. If the erase block is full of data during the writing of data,the operations at the steps ST103, 104 and 105 are executed to obtain anempty block so that the remaining data is written in the obtained memoryblock.

After doing these operations, if no data is left (ST108), the storageinformations of the erase block management area and the memory blockmanagement area are made to indicate the data-written states. Then, thedirectory information is made to be set as "closed" (ST109), and theoperation is terminated. If no empty block is found at the step ST103,no more data is allowed to be stored. Hence, the operation isterminated.

In turn, the description will be oriented to the flow of erasing thedata stored in the flash memory at an erase block unit with reference toFIG. 8. At first, it is checked that the operation such as sending ofdata from the memory, receipt of data in the memory or response of ananswering phone is terminated (ST 201). Next, the erase block isexamined and it is checked that the block corresponds to the head one(NO. 1) of the blocks NOs. 1 to 16 indicated in the left side of FIG. 2(ST 202). Then, based on the block using information of the erase blockmanagement area, it is also checked whether or not the erase block is inuse (ST203). If it is not in use, it is checked whether or not the eraseblock is the last erase block (NO.16) (ST204). If it is not, a check isdone to determine whether or not the erase block corresponds to the nextone (ST205).

If at the step ST203 the erase block is in use, it is determined whetheror not the data in all the memory blocks of the erase block is to beerased (ST210). If the data is to be sent (e.g., fax transmission) thedata is erased upon termination of sending of the data , while if thedata is to be received (e.g., fax reception), the data is erased upontermination of recording of the data. If one erase block contains evenone piece of data (one memory block) not to be erased, the operationgoes to the step ST204 without erasing the erase block. If all the datacontained in the erase block are to be erased, the erase block isallowed to be erased (ST211). Then, the erase block whose data is erasedis chain-coupled to the tail of the empty block group as shown in FIG. 4(ST212). This chain-coupling is logically executed based on theinformation stored in the erase block management area shown in FIG. 3.It is therefore unnecessary to change the initial storage informationupon erasure. That is, in the storage information, the block erasingstate is "not", the block using information is "not used", . . . , andthe number of the next erase block indicates the tail "FF".

After checking the next erase block at the step ST205, it is checkedwhether or not the request for the operation at the step ST201 is issued(ST206). If it is issued, it is checked whether or not the number ofempty erase blocks is equal to or more than the regulated value (ST207).To count the number of the empty erase blocks, the block usinginformation of the overall erase block management area is checked. Thatis, if the information about each erase block indicates "not used", thenumber of the "not used" erase blocks is counted. The regulated value isdefined by the data about sending and receipt treated by the facsimileapparatus. If the number of the empty blocks is equal to or more thanthe regulated value, the erasing work is interrupted, the requestedoperation is executed (ST208). After the operation is terminated(ST209), the serial processes at the steps ST203, ST204 and ST210 toST212, which was executed by the first erase block, are carried out forthe next erase block. These processes are repeated until the subjectblock reaches the last one (NO.16) (ST204). By performing such anerasing operation periodically or in response to an indication given bythe operation unit 5, it is possible to efficiently use the flash memory11.

Next, the description will be oriented to how an operator erases thecontent of the memory part. In the case of a message received by theanswering phone, the message cannot be erased only after the receiverlistens to the message. Further, for the facsimile bulletin board, if nonotice period is indicated, an operator other than the person postingthe notice cannot understand how long the bulletin board is to benoticed. To cope with this, the facsimile apparatus has to be arrangedso that the noticer can give a proper indication of erasing the boardthrough the operation unit 5. In this case, in order for the operator tomake sure of the erasure, the erasing state is displayed on the displayunit 6.

FIG. 9 shows a display example appearing when the data is erased. Thisexample concerns with the case that the operator erases the notice onthe facsimile bulletin board. Normally, the display unit 6 displays thedata and the time. If an indication of erasing the board is given, tomake sure of the indication, the sentence "Is Bulletin Board Erased ?"appears on the display unit 6. Next, "Under Erasing" appears thereon.Then, the original date and time are displayed. This shift of thedisplay is so short that the operator can feel the erasure isimmediately terminated.

To erase one erase block, however, the facsimile apparatus of thisembodiment needs about two seconds. It means that a considerable time isrequired for erasing the content stored in plural erase blocks. On thedisplay, therefore, the block erasing state of the erase blockmanagement area is shifted from "yet" to "done" and the data erasion ofthe erase block is terminated. After this display, the erasing operationis performed along the flowchart shown in FIG. 8. This makes it possibleto realize a more convenient facsimile apparatus.

As is obvious from the above description, according to the presentinvention, if the facsimile apparatus uses such a memory as allowing thedata to be erased in blocks, the memory may hold the same operativity asthe conventional DRAM or SRAM if the way of use is properly selected.Further, the memory used in the present invention does not need a powersupply for holding the stored content. It means that the memory may beeasily used. The present invention has the following effects (1) to (8).

(1) In the case of using the memory in bits, by setting the initialstate as a waiting state and the state reversed from the initial stateas a starting state, like the conventional memory, the memory may beused as a flag.

(2) Since the memory is managed so that one block stores only the samekind of information, the period when the erasing condition of the blockbecomes satisfactory is made shorter and thereby the data of the blockmay be erased quickly. This enables to enhance the efficiency of usingthe memory.

(3) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, the memory may be arranged so that oneblock stores only the sending information, while another block storesonly the received information. In this arrangement, the period when theerasing condition is made satisfactory in each block is made shorter andthereby the erasure is made faster. This enables to enhance theefficiency of utilizing the blocks in the memory.

(4) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, the empty blocks are logically arranged ina line so that these blocks are picked from the head. As such, theprobability of evenly using the blocks is made higher and thereby thefailure takes place less frequency. This leads to extending the life ofthe memory.

(5) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, the sending information and the receivedinformation are stored in respective blocks. This serves to shorten theperiod when the erasing conditions of the informations are met.Immediately when the conditions are met, these informations are erased.This makes it possible to process a lot of data even with a small amountof volume.

(6) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, if the block data is erased after thecondition is met, the block is connected to the tail of the emptyblocks, so that the empty blocks are coupled in the using sequence. Thismakes it possible to evenly use the blocks, thereby extending the lifeof the memory.

(7) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, the block data is erased if the erasingcondition of the block is met. When the request for sending or receiveddata is issued while the data is being erased, it is checked that thenumber of the empty blocks is equal to or more than the predeterminednumber and then the operation is determined to be done. Hence, duringthe operation, the memory volume is secured. The data is allowed to bepositively sent or received.

(8) In a case that the facsimile apparatus uses a memory which enablesto store data only in blocks, when an operator erases data in the block,the termination of erasure is displayed at a time when the managementdata of the block requested to erase the erasing condition is erased.Then, the stored content is erased. By this operation, the operator canimmediately make sure that the content is erased and does not have towait until the actual erasure is done.

What is claimed is:
 1. A facsimile apparatus comprising:reading meansfor reading a manuscript to obtain transmission information;communication means for transmitting the transmission information to anetwork and receiving reception information from the network; a memoryhaving a storage area divided into plural blocks and erasable only inunits of said plural blocks; erasing means for erasing informationstored in each of said plural blocks; and control means for counting anumber of empty blocks when a request for registering said transmissioninformation is issued by said reading means or a request for receivingsaid reception information is issued by said communication means whileinformation stored in any block is being erased (i) to control saiderasing means to stop an erasing operation when a number of the emptyblocks is not less than a predetermined number and (ii) to control saiderasing means to erase information until the number of the empty blocksreaches said predetermined number when the number of the empty blocks isless than said predetermined number, and for controlling said readingmeans to register said transmission information or controlling saidcommunication means to receive said reception information.
 2. Afacsimile apparatus comprising:a memory having a storage area dividedinto plural blocks and erasable only in units of said plural blocks;operating means for providing a command to do an erasing operation foreach of said plural blocks of said memory; display means for displayinga message indicating that data is being erased for a shorter time than atime needed for said erasing operation before the erasing operation isstarted in accordance with a handling of said operating means; andcontrol means for controlling said memory to erase a plurality of saidplural blocks of said memory after said message is displayed in saiddisplay means.
 3. A facsimile apparatus according to claim 1, whereinsaid plural blocks comprise:a block for storing one of a receivedtelephone message, an outgoing telephone message, manuscript informationto be transmitted according to a timer and information to be used in afacsimile-on-demand system; and blocks for storing said transmissioninformation and said reception information.
 4. A facsimile apparatusaccording to claim 2, wherein said plural blocks comprise:a block forstoring one of a received telephone message, an outgoing telephonemessage, manuscript information to be transmitted according to a timerand information to be used in a facsimile-on-demand system; and blocksfor storing transmission information and reception information.